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  <title>使用用户自定义的比较函数对数组中的键名进行排序</title>
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 <body class="docs"><div id="layout">
  <div id="layout-content"><div id="function.uksort" class="refentry">
   <div class="refnamediv">
    <h1 class="refname">uksort</h1>
    <p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">uksort</span> &mdash; <span class="dc-title">
     使用用户自定义的比较函数对数组中的键名进行排序
    </span></p>

   </div>
 <div class="refsect1 description" id="refsect1-function.uksort-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>uksort</strong></span>
    ( <span class="methodparam"><span class="type">array</span> <code class="parameter reference">&$array</code></span>
   , <span class="methodparam"><span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <code class="parameter">$key_compare_func</code></span>
   ) : <span class="type">bool</span></div>

    <p class="para rdfs-comment">
     <span class="function"><strong>uksort()</strong></span> 函数将使用用户提供的比较函数对数组中的键名进行排序。如果要排序的数组需要用一种不寻常的标准进行排序，那么应该使用此函数。
    </p>
  <blockquote class="note"><p><strong class="note">Note</strong>: 
 <p class="para">
  If two members compare as equal, their relative order in the sorted array is undefined.
 </p>
</p></blockquote>

   </div>

 <div class="refsect1 parameters" id="refsect1-function.uksort-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    
     <dt>
<code class="parameter">array</code></dt>

     <dd>

      <p class="para">
       输入的数组。
      </p>
     </dd>

    
    
     <dt>
<code class="parameter">key_compare_func</code></dt>

     <dd>

      <p class="para">
       在第一个参数小于，等于或大于第二个参数时，该比较函数必须相应地返回一个小于，等于或大于 0 的整数。
      </p>
      <div class="methodsynopsis dc-description"><span class="methodname"><span class="replaceable">callback</span></span> ( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$a</code></span>, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$b</code></span> ) : <span class="type">int</span></div>

     </dd>

    
   </dl>

  </p>
 </div>

 <div class="refsect1 returnvalues" id="refsect1-function.uksort-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   成功时返回 <strong><code>TRUE</code></strong>， 或者在失败时返回 <strong><code>FALSE</code></strong>。
  </p>
 </div>

 <div class="refsect1 examples" id="refsect1-function.uksort-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-6121">
    <p><strong>Example #1 <span class="function"><strong>uksort()</strong></span> 例子</strong></p>
    <div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">function&nbsp;</span><span style="color: #0000BB">cmp</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">)<br />{<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">preg_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">'@^(a|an|the)&nbsp;@'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">''</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$a</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$b&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">preg_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">'@^(a|an|the)&nbsp;@'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">''</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">strcasecmp</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">);<br />}<br /><br /></span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #DD0000">"John"&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"the&nbsp;Earth"&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">2</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"an&nbsp;apple"&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">3</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"a&nbsp;banana"&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">4</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">uksort</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"cmp"</span><span style="color: #007700">);<br /><br />foreach&nbsp;(</span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">as&nbsp;</span><span style="color: #0000BB">$key&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">$value</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"</span><span style="color: #0000BB">$key</span><span style="color: #DD0000">:&nbsp;</span><span style="color: #0000BB">$value</span><span style="color: #DD0000">\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
    </div>

    <div class="example-contents"><p>以上例程会输出：</p></div>
    <div class="example-contents screen">
<div class="cdata"><pre>
an apple: 3
a banana: 4
the Earth: 2
John: 1
</pre></div>
    </div>
   </div>
  </p>
 </div>

 <div class="refsect1 seealso" id="refsect1-function.uksort-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="usort.html" class="function" rel="rdfs-seeAlso">usort()</a> - 使用用户自定义的比较函数对数组中的值进行排序</span></li>
    <li class="member"><a href="array.sorting.html" class="link">数组排序函数对比</a></li>
   </ul>
  </p>
 </div>

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